LOS ANGELES — Seventy years ago, the world was convinced that Louis Zamperini was dead. There had been no word of the track star and former Olympian since his World War II bomber crashed into the Pacific Ocean. The military told his parents he was dead, and an annual collegiate track competition named one of its races in his memory.

But Zamperini was alive, and very much so. After surviving 47 days in a life raft in shark-infested waters and enduring two years as a Japanese prisoner of war, Zamperini was liberated in time to attend the second running of the invitational mile that had been named in his memory. It was a story fitting for a man who lived a life on the edge of endurance, an ordinary man who did extraordinary things — all while sustained by a hope and strength that at times seemed superhuman.

Zamperini, a war hero, Olympian and the subject of a celebrated book and upcoming movie on his harrowing story of survival against all odds, died after a long battle with pneumonia, his family said Thursday in a statement. He was 97.

Zamperini outlived almost all of those who watched him weave his way through his remarkable life, but the outpouring from those who came to know and love the man in his later years was as immediate and intense as the life he lived.

Laura Hillenbrand, the author of the best-selling book "Unbroken: A World War II Story of Survival, Resilience, and Redemption," said over countless hours of interviews Zamperini became a surrogate grandfather and beloved friend who helped her cope with her own debilitating illness, chronic fatigue syndrome.

"In a life of almost unimaginable drama, he experienced supreme triumphs, but also brutal hardship, incomprehensible suffering, and the cruelty of his fellow man. But Louie greeted every challenge of his long journey with singular resilience, determination and ingenuity, with a ferocious will to survive and prevail, and with hope that knew no master," said Hillenbrand, whose book is being made into a movie directed by Angelina Jolie and is scheduled for a December release by Universal.

"His story is a lesson in the potential that lies within all of us to summon strength amid suffering, love in the face of cruelty, joy from sorrow," she said in the statement, which was issued through her publisher, Random House.

Jolie echoed those sentiments Thursday.

"It is a loss impossible to describe," she said in a statement. "We are all so grateful for how enriched our lives are for having known him. We will miss him terribly."

Born on Jan. 26, 1917, Zamperini's larger-than-life story began with a blue-collar upbringing in Olean, a city in western New York. When he was 2, the family moved to Southern California, where he spent a rebellious childhood before channeling his energy and tenacity into sports. He started with boxing, to defend himself from bullies, but became a world-class runner after joining his high school track team.

In 1934, Zamperini — nicknamed the "Torrance Tornado" for his hometown of Torrance, California — broke the 18-year-old interscholastic record for the mile in 4:21.2, a mark that would stand for 20 years.

A track star at the University of Southern California, Zamperini competed in the 5,000-meter run at the 1936 Berlin Olympics. He finished eighth but caught attention by running the final lap in 56 seconds — and grabbed headlines by stealing a Nazi flag.

But it was Zamperini's incredible World War II story that captured the imagination of millions back home.

He was a bombardier on a U.S. Army Air Forces bomber that crashed in the Pacific Ocean during a reconnaissance mission. He and one of the other surviving crew members drifted for 47 days on a raft in shark-infested waters, drinking rain water and eating fish and birds they caught with their bare hands, before being captured by Japanese forces. A third man died before they reached land.

"Forty-seven days in a raft, you learn the value of water more than anything in the world," he told the AP in a 2003 interview. "We prayed for rain to have something to drink. When you're hungry, you eat anything. We caught a shark. We caught an albatross that tasted like a hot fudge sundae."

When he and his surviving raft-mate, pilot Russell Allen Phillips, reached land on the Marshall Islands, they were captured by the Japanese, who had also strafed their raft from the air and riddled it with bullet holes.

"I thought to myself, 'Six weeks ago, I was a world-class athlete,'" he told the AP. "And then, for the first time in my life, I cried."

Zamperini would spend more than two years as a prisoner of war being shuttled among Japanese prison camps, where he survived beatings, starvation, debilitating illnesses and psychological torture designed to break him down and make an example of the famous Olympian-turned-war hero.